Urea compounds with selective herbicidal activity

ABSTRACT

UREAS OF THE FORMULA   1-((CH3-)2-N-),2-X,4-(CH3-N(-R)-C(=Y)-NH-)BENZENE   THEIR ACID ADDITION SALTS AND USE IN HERBICIDAL PREPARATIONS ARE DISCLOSED. IN THE ABOVE FORMULA R REPRESENTS A HYDROGEN ATOM OR A LOWER ALKYL RADICAL, OR A LOWER ALKOXY RADICAL, Y REPRESENTS AN OXYGEN OR SULFUR ATOM AND X IS A CHLORINE OR BROMINE ATOM OR THE TRIFLUOROMETHYL RADICAL. THEY ARE ESPECIALLY SUITED TO CONTROL THE GROWTH AND PROLIFERATION OF WEEDS IN CROPS OF CEREALS.

United States Patent Ofiice 3,803,198 Patented Apr. 9, 1974 US. Cl. 260-453 R 6 Claims ABSTRACT OF THE DISCLOSURE Ureas of the formula their acid addition salts and use in herbicidal preparations are disclosed. In the above formula R represents a hydrogen atom or a lower alkyl radical, or a lower alkoxy radical, Y represents an oxygen or sulfur atom and X is a chlorine or bromine atom or the trifluoromethyl radical. They are especially suited to control the growth and proliferation of weeds in crops of cereals.

CROSS REFERENCE This application is a continuation-in-part of my application Ser. No. 879,617, filed Nov. 24, 1969 which itself is a continuation-in-part of my application Ser. No. 745,108 filed July 16, 1968 both now abandoned.

DESCRIPTION OF THE INVENTION The present invention provides pesticidal preparations, especially preparations for inhibiting the growth and proliferation of undesired plants, such as wild grasses and weeds, in culture crops such as cereals which comprise as the active ingredient one or more compounds of the general formula wherein R represents a hydrogen atom, a lower alkyl or a lower alkoxy radical, Y represents an oxygen or sulphur atom and X represents a chlorine or bromine atom or the trifluoromethyl group, and acid addition salts thereof with an inorganic or organic acid, together with a carrier. The preparations may also contain one or more of the following additives: a solvent, a dispersing agent, a wetting agent, an adhesive, a binder, a thickner and/ or fertilizer and/or optionally other known pesticides, especially materials for combating undesired plant growth.

As acids which may be used for salt formation for the active ingredients of Formula I there may be mentioned for example the following inorganic acids: sulphuric acid, hydrochloric acid, hydrobromic acid, sulphamic acid and nitric acid; and organic acids: acetic acid, trichloracetic acid, fumaric acid, maleic acid, benzoic acid, trichlorobenzoic acid, trichloraminopicolinic acid, dichloromethoxybenzoic acid, phthalic acid, tetrachlorophthalic acid and nicotinic acid.

Lower alkyl means that the carbon chain contains 1 to 4 carbon atoms and may be straight or branched. Examples of such lower alkyl radicals are methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec. or tert. butyl.

Preferred, however, are straight chained radicals containing 1 or 2 carbon atoms.

The statement made for lower alkyl is also valid for lower alkoxy.

Preferred compounds correspond to the formula wherein R has the meanings given in Formula I, and X stands for chlorine or bromine.

The ureas of the Formula I and their acid addition salts with an organic or inorganic acid are new and thus constitute part of this invention.

The preparations which contain an active ingredient of Formula I may, depending on the amount used, be employed as total herbicides or as selective herbicides in culture plants, for combating wild grasses and/or weeds.

By weeds there may be also understood undesired culture plants, that is to say plants which have previous ly been cultivated. The compounds defined above are furthermore also suitable for use as active substances for exerting other inhibiting influences on plant growth, especially defoliation, for example, of cotton plants, acceleration of ripening by premature drying-out, for example of potato plants, and also for the reduction of fruit setting, retardation of flowering or prolongation of the storability of the harvest products. Furthermore, the use of growth-inhibiting agents can under certain circumstances not only lead to an increase in yield as a result of suppressing the weeds but also a result of the fact that these agents counteract influences which can stimulate the growth of the culture plants in an undesired direction, for example, high temperatures or excessive use of fertilizer. Employed in small quantities which do not permit any phytotoxic side-efiects to arise, the new preparations can also be used for combating phytopathogenic bacteria and fungi.

In certain dilutions, the new preparations can also be worked into the soil, or the soil may be impregnated with them; this type of treatment serves to combat plantparasitary nematodes.

Many of the active substances defined by Formula I also possess a strong action against gastropodes, waterpests, as well as algae, sedentaria, slime baceteria and water-weeds.

The preparations of the invention, for influencing plant growth and combating weeds can be used in the form of solutions, emulsions, suspensions, granules or dusting agents. The form used entirely depends on the end to be achieved. At the same. time all forms of use must ensure that the active substance can be finely distributed. The action can, especially in total suppression of plant growth, in premature drying-out and in defoliation, be reinforced by the use of carriers which are in themselves phytotoxic, for example, high-boiling mineral.

The aqueous preparations are preferably in the form of emulsions and dispersions. The substances, either per se or in one of the abovementioned solvents, may be homogenized in water, preferably by means of a wetting agent or a dispersing agent. Quaternary ammonium compounds may be mentioned as examples of cationic emulsitiers or dispersing agents, soap, soft soap, aliphatic longchain sulphuric acid monocsters, alkylphenylsulphonic acids, long-chain alkoxyacetic acids as anionic agents and polyethylene oxide condensation products of higher fatty acids, higher alcohols and higher amines as non-ionic agents. On the other hand, it is also possible to manufacture concentrates, suitable for dilution with water before use, comprising the active substance, emulsifier or dispersing agent and optionally a solvent. Dusting agents can initially be manufactured by mixing or joint grinding of the active substance with a solid carrier. Suitable carriers are: talc, diatomaceous earth, kaolin, bentonite, calcium carbonate, boric acid, tricalcium phosphate, but also wood flour, cork powder, charcoal and other materials of vegetable origin. n the other hand the substances can also be applied to the carriers by means of a volatile solvent. Powder-form preparations and pastes can be rendered capable of suspension in water and used as spraying agents by adding wetting agents and protective colloids.

Since the active substances according to the invention include both solid and also liquid substances having substantially the same herbicidal activity, it is easily possible to manufacture both liquid concentrates for aqueous emulsions and also powder-form or paste-form concentrates for aqueous suspensions, having a high concentration of active substance.

The various forms which may be used may in the usual manner be more closely suited to the end to be achieved by adding substances which improve the distribution, the adhesion, the rain resistance and optionally the penetrating power, for example, fatty acids, resins, wettingiagents, .glue, casein or alginates. Equally, their biological action can be broadened by adding substances having bactericidal or fungicidal properties or properties which also influence plant growth, as well as fertilizers.

The active substances of Formula I can be easily manufactured as follows:

A reactive derivative of carbonic acid or thiocarbonic acid is reacted, in optional sequence, with a dimethyl aniline of formula wherein Y has the meanings hereinbefore defined, and a methyl amine of formula wherein R has the meanings hereinbefore defined.

According to the process, a possible procedure is, for example, to react an aniline of Formula IH with phosgene or thiophosgene and allowing the resulting carbanilic acid chloride or the corresponding iso(thio)cyanate to react further with an amine of Formula IV. Conversely it is also possible first to allow an amine of Formula IV to react with phosgene or thiophosgene and then to react the resulting carbamic acid chloride (or, if R is hydrogen, the resulting iso(thio)cyanate) further with an aniline of Formula IH. Instead of phosgene or thiophosgene it is also possible to react a halogenocarbonic acid ester, preferably an aryl ester, with an aniline of Formula III or with an amine of Formula IV and to amidize the resulting urethane with a corresponding amine or aniline. It is also possible to react an aniline of Formula III with EXAMPLE 1 (a) 38.4 g. of 1,2-dichloro-4-nitrobenzene in 200 ml. of alcohol are heated with 52 ml. of 40% strengthdimethylamine for 5 hours to 150 C. The mixture is allowed to cool and the resulting 3-chloro-4-dimethylaminonitrobenzene is precipitated by adding water. 39.5 g., melting point 79-80 C.

(b) 588 g. of 3-chloro-4-dimethylaminonitrobenzene in 1.4 l. of dimethylformamide and 20 g.;of Raney nickel are hydrogenated with hydrogen. After completion of the reaction the catalyst is filtered olf, the solution is ev-apo rated and the residue is distilled in vacuo. Yield 456 g.; boiling point C./0.8 mm. Hg. 1 Y 3 "1 (0) 170.5 g.-of 3-chloro-4-dimethylaminoaniline in 500 ml. of acetonitrile are stirred for 2 days with 85 g. of pyridine and g. of dimethylcarbamoyl chloride. The product is precipitated by adding water and g. of N',N'-dimethyl-N (3 chloro 4-dimethylaminophenyl) urea are obtained. Melting point 127- C. [Compound'No.

The following compounds are manufactured in a similar manner.

011. ,N-QNE-C o-nn-om l Br (CH4)zNNH-C s-Nn-orn EXAMPLE 2 40 parts of the active substance No 1 and 400 parts of talc are ground in a ball mill to maximum fineness. The resulting mixture serves as a dusting agent.

EXAMPLE 3 20 parts of the active substance No. 3 are dissolved in a mixture of 100 parts of diacetone-alcohol, 16 parts of xylene and 20 parts of an anhydrous high molecular con- 

